For a number of years, the press of population and the greatly increasing cost of labor and materials has created a demand for housing structures that may be erected with a minimum use of skilled labor using premanufactured structural members of a housing "package" that may be readily transported to the building site. However, although the demand exists, the success of "prefabricated" housing has not met with anticipated expectations due to a myriad number of problems. One of these problems exists in the design and manufacture, as well as structural attachment, of large structural panels which are most often used in such "prefabricated" structures. These panels, which often comprise the walls, flooring, and roof of such "prefabricated" structures may, because of economics and design consideration, be fabricated in relatively large dimensions in the order of, perhaps, 8 to 9 feet in height or width, and 20 to perhaps 40 feet or even longer in length. In the larger sizes, such panels, depending upon the material used in their construction, may weigh in the order of 800 to 1000 pounds.
In the last decade or so, with the availability of rigid synthetic polymeric foams, it has become advantageous to construct panel members utilizing rigid foamed materials as core members laminated between outer "skins" that may comprise plywoods, metal sheets, sheet rock, pressed board, and the like. The skins are laminated to the foamed core most generally by applying adhesive therebetween and forcing the same together in a tight bond with large presses.
Because the panels are relatively thin in relation to their overall horizontal dimensions, it is difficult to prevent warping or twisting of the panels either during manufacture or afterwards in use. It is therefore common to provide some type of a frame for the panel structures. These frames may comprise only peripheral members, but, frequently, with additional internal studs or stiffeners interconnecting the external frame members. Most often, the frame members, both peripheral and internal, are constructed from either metal or wood sections.
Where common wood framing is used, the frames are subject to excessive warping. In addition, such wood framing usually requires careful handling and extensive labor during erection in order to provide tight joints and proper alignment of the panels.
Panels utilizing metal frames most often employ rectangular channels and mating shoes for effecting joints between panels. Such rectangular shaped channels and shoes are, however, susceptable for handling damage and require careful alignment for proper seating.
Other prior panel structures utilize spline and extrusions for joint structures. Such systems, however, generally require complicated spline shapes; they are usually expensive to manufacture and are poor structurally. Their use is usually limited to readily accessible situations.
All such prior panel edge structures tend to be very rigid and non-resilient. Thus, any variations in core dimensions tend to produce weakened lamination areas that are subject to delamination during stress in use.